At present, the next generation network (NGN), which is one of hotspot research subjects in the current communication standard field, uses the Internet protocol (IP) packet technology as a bearer network technology and integrates with fixed communication and mobile communication so as to provide more abundant multimedia services, such as emerging services having real-time requirements (IP television, video conference, multimedia distance education, video on demand, etc.), which require that a communication network should be able to provide support for high efficient end-to-end Quality of Service (QoS). Meanwhile, users' requirements for network Quality of Service are higher and higher. Therefore, how to provide the end-to-end QoS will be one of core problems of the NGN.
The International Telecommunication Union-Telecommunication Standardization Sector (ITU-T), which is the telecommunication standardization sector of the International Telecommunication Union (ITU), has constituted a standard regarding to resource and admission control. In the latest resource and admission control function (RACF) draft published by the ITU-T, a function frame of the RACF is provided, as shown in FIG. 1. The RACF is comprised of two portions, a policy decision functional entity (PD-FE) and a transport resource control functional entity (TRC-FE). The TRC-FE interacts with a transport function through an Rc interface and interacts with a transport resource enforcement functional entity (TRE-FE) through an Rn interface; whereas the PD-FE interacts with the TRC-FE through an Rt interface, interacts with a customer premises network (CPN) through an Rh interface, interacts with a policy enforcement functional entity (PE-FE) through an Rw interface, interacts with a service control function (SCF) in a service layer through an Rs interface, interacts with a network attachment control function (NACF) through an Ru interface, and interacts with other next generation networks through an Ri interface.
In addition, the PD-FE is independent of both the transport technology and the SCF, and makes a final decision of resource and admission control based on network policy rules, service information provided by the SCF, transport layer subscription information provided by the NACF and resource availability decision results provided by the TRC-FE.
The TRC-FE is independent of services, but is associated with the transport technology. The TRC-FE is responsible for collecting and maintaining transport network information and resource state information. After receiving a resource request from the PD-FE, the TRC-FE performs resource-based admission and control based on the QoS, priority requirements, resource availability information and transport-related policy rules.
The transport layer is comprised of a policy enforcement functional entity (PE-FE) and a transport resource enforcement functional entity (TRE-FE). The PE-FE performs policy rules sent down by the PD-FE. The PE-FE, which is a packet to packet gateway, may be located between a customer premises network (CPN) and an access network, between an access network and a core network, or between different operator networks, and is a key node for supporting dynamic QoS control, port address translation control and network address translation (NAT) traversal. The TRE-FE performs transport resource policy rules sent down by the TRC-FE, and their scope and functions and the Rn interface remain to be further studied and are not within the research scope of the R2 stage.
At present, in order to support application of nomadicity, a diagram of a RACF nomadicity scenario is given, as shown in FIG. 2. In FIG. 2, a SCF belongs to a NGN home operator and interacts with a PD-FE of the NGN home operator. The PD-FE of the NGN home operator interacts with a PD-FE of a NGN visit operator through an Ri interface; PD-FE interacts with PE-FE and TRC-FE in its network through an Rw interface and an Rt interface, respectively.
In order to support application of wholesale, a diagram of a RACF wholesale scenario is given, as shown in FIG. 3. In FIG. 3, a SCF belongs to a NGN retail service provider that is generally an actual service provider. A PD-FE of the NGN retail service provider interacts with a PD-FE of the NGN wholesale service provider that is generally a network operator through an Ri interface. In the wholesale scenario, the network operator uses a network level as infrastructure for opening to multiple service providers in a wholesale way and does not provide services; whereas the service provider provides various services. When users are in this scenario, they access networks via a network of the network operator to visit the networks and enjoy the services provided by the service providers.
It can be seen from the two scenarios described above that RACF network configurations of nomadicity and wholesale are same and corresponding resource and admission control methods are consistent as well. Hereinafter, PD-FEs of the NGN home operator and the NGN retail service provider will be denoted by PD-FE(H); PE-FEs of the NGN home operator and the NGN retail service provider will be denoted by PE-FE(H); PD-FEs of the NGN visit operator and the NGN wholesale service provider will be denoted by PD-FE(V); PE-FEs of the NGN visit operator and the NGN wholesale service provider will be denoted by PE-FE(V); and TRC-FEs of the NGN visit operator and the NGN wholesale service provider will be denoted by TRC-FE(V).
In the existing nomadicity/wholesale scenario, the interaction between the PD-FE(H) and PR-FE(H) is not considered. FIG. 4 is a flow chart of resource request in the related art, which comprises the following steps:
401, A user initiates a service request and sends a request message to a SCF to trigger the SCF to generate a resource initialization request.
402, The SCF determines QoS requirement parameters (e.g., bandwidth, service type, etc.) of the services to be requested and then sends the resource initialization request message (reservation) containing media stream description and the QoS parameters to a PD-FE(H) to request the RACF to authorize and reserve QoS resources.
403, The PD-FE(H) inspects for authorization the resource initialization request, including verifying whether the requested QoS resources are consistent with local operator policy rules and user subscription information from the NACF; if the check for authorization is passed, the PD-FE(H) makes initial policy decision for the service request based on the user subscription information, the local operator policy rules and service information.
404, Since the PD-FE(H) does not have transport layer resources requested, the resource initialization request message is further sent to PD-FE(V).
405, The PD-FE(V) inspects for authorization the resource initialization request, including verifying whether the requested QoS resources are consistent with the local operator policy rules.
406, The PD-FE(V) decides (i.e., selects) an access network and a core network which the requested QoS resources are involved with and then sends the resource initialization request message (availability check) to a corresponding TRC-FE(V) based on the decision result to inspect resource availability of the involved network.
407, The PD-FE(V) makes final admission decision based on the authorization check result in step 405 and the check result of the resource availability in step 406; if the requested QoS resources are rejected, the PD-FE(V) sends a resource initialization response message containing the reason for rejection to the PD-FE(H).
408, If the final decision policy is required to be installed in the PE-FE, the PD-FE(V) sends the resource initialization request message to the PE-FE(V) to install the final decision policy.
409, The PE-FE(V) installs the final decision policy from the PD-FE(V) and sends the resource initialization response to the PD-FE(V).
The step 408 and 409 are optional.
410, The PD-FE(V) sends the resource initialization response to the PD-FE(H).
411, The PD-FE(H) sends the resource initialization response to the SCF.
It can be seen from the above that there is no interaction between the PD-FE(H) and PR-FE(H) in the existing nomadicity/wholesale scenario. Since it is equivalent to being located between the access network and the core network for the PE-FE(H) in this scenario, it implements a core boundary gateway function and has functions, such as NAT traversal, port address translation control, gating, QoS marking and resource synchronization, all of which are required to be completed under the control of the PD-FE(H). If there is no interaction between the PD-FE(H) and PE-FE(H), the corresponding functions of PE-FE(H) cannot be implemented such that service requests from users can not be satisfied.